The present disclosure relates to a sheet conveying device for conveying sheets, an image reading device provided with the sheet conveying device, and an image forming apparatus provided with the sheet conveying device.
An image forming apparatus utilizing electrophotography such as a copying machine, a printer, and a facsimile machine is configured to form a toner image by supplying a developer onto an electrostatic latent image formed on an image carrier (such as a photosensitive drum or a transfer belt) and by developing the electrostatic latent image. The toner image on the image carrier is transferred onto a sheet by a transfer device. The sheet carrying the transferred toner image is conveyed to a fixing device. After the sheet is subjected to a fixing process in the fixing device, the sheet is discharged onto a predetermined sheet discharge portion.
In the thus-configured image forming apparatus, the sheet is conveyed from a sheet storing portion to a transfer position facing the transfer device. Then, the sheet is conveyed to the sheet discharge portion from the transfer position via the fixing device. Conventionally, there is known a technology, in which a sheet is conveyed while being held by a drive roller which is driven and rotated, and a driven roller which is driven and rotated with the drive roller. The drive roller is provided with a rubber layer on an outer surface thereof to have a predetermined friction coefficient with respect to the sheet. On the other hand, in many cases, the driven roller is made of a resin material.
Conventionally, there is known a technology, in which a driven roller is pressed against a drive roller, while being rotatably supported by a support member constituted of a plate spring. The support member has one end thereof which supports the driven roller, and has the other end thereof which is screw-fastened to a casing. Further, a shaft of the driven roller is inserted in a groove-shaped bearing member made of a resin material to rotatably support the driven roller. Furthermore, the driven roller is pressed against the drive roller by urging the plate spring toward the shaft of the driven roller.
In the aforementioned technology, there may be generated noise caused by contact between the shaft of the driven roller and a bearing portion by a long period of use in a state that the shaft of the driven roller is inserted in the groove-shaped bearing member made of a resin material.
An object of the present disclosure is to provide a sheet conveying device that enables to suppress generation of noise caused by contact between resin members in a bearing portion of a driven roller.